1. Abrahamson, E. W., Wiesenfeld, J. R.: The structure, spectra, and reactivity of visual pigments. In: Handbook of sensory physiology, vol. VII/I (ed. H. J. Dartnall), pp. 69?121. Berlin-Heidelberg-New York: Springer 1972
2. Adler, A. J., Greenfield, N. J., Fasman, G. D.: Circular dichroism and optical rotatory dispersion of proteins and polypeptides. In: Methods in enzymology, vol. 24, pp. 675?735. New York: Academic Press 1972
3. Azuma, M., Kito, Y.: Studies on optical rotation, circular dichroism and amino acid composition of rhodopsin. In: Annual report of biological works, faculty of science, Osaka University, vol. 15, pp. 59?69. Toyonaka: Osaka University Press 1967
4. Becher, B., Cassim, J. Y.: Spectroscopic studies of reversible bleaching in the purple membrane of Halobacterium halobium. Abstracts American Society for Photobiology (1975)
5. Beychok, S.: Side-chain optical activity in cystine-containing proteins: circular dichroism studies. Proc. nat. Acad. Sci. (Wash.) 53, 999?1006 (1965)